# Foundation vs. Instruct vs. Thinking Models

DevFeed: [Foundation vs. Instruct vs. Thinking Models](<https://devfeed.tech/articles/foundation-vs-instruct-vs-thinking-models-29076.md>)

Original publisher: [Read original article](<https://blog.alexewerlof.com/p/base-models-vs-instruct-models>)

Author: Alex Ewerlöf

Published: 2025-12-24T07:07:00Z

Content type: opinion

Language: en

Sources: [Alex Ewerlof Notes](<https://devfeed.tech/sources/alex-ewerlof-notes.md>)

Topics: [foundation-models](<https://devfeed.tech/topics/foundation-models.md>), [Large Language Model](<https://devfeed.tech/topics/llm.md>), [AI-assisted coding](<https://devfeed.tech/topics/ai-assisted-coding.md>)

Tags: [ai](<https://devfeed.tech/tags/ai.md>), [code-completion](<https://devfeed.tech/tags/code-completion.md>), [foundation](<https://devfeed.tech/tags/foundation.md>), [llms](<https://devfeed.tech/tags/llms.md>), [models](<https://devfeed.tech/tags/models.md>)

## AI overview

This article explains the distinction between base and instruction-oriented language models using a software metaphor. It describes base models as pretrained systems that predict the next token from learned patterns, without an inherent concept of questions, answers, or instructions, and discusses code completion as one use case.

## Source excerpt

A Senior Engineer's Mental Model for AI